Many studies have shown that stem cells are self-renewable, can differentiate into other functional cells under the right conditions, thus the stem cells could be effective for the treatment of difficult human diseases. However, a normal mature tissue contains very little stem cells. So how to rapidly proliferate and culture stem cells in vitro becomes an important technique in studying the action mechanisms of stem cells and exploring their application methods in treating human diseases.
Although stem cells are in a very small amount, they are widely distributed in various mammalian tissues and organs, including but not limited to, bone marrow, umbilical cord, adipose tissues, brain, retina, heart, liver, lung and skin. Many studies have shown that, the low amount of stem cells can be further proliferated by appropriate methods in vitro. The most routine culture medium used to culture stem cells is a culture medium with some fetal calf serum. However, the stem cells cultured in this kind of medium, are not only growing slowly, but their differentiation potential into functional cells is also greatly reduced after proliferating over 5 generations, and the potential non-reproducibility between different bovine serum batches also greatly affect its large scale applications. On the other hand, bovine serum is heterologous to human, which limits its clinic applications. Therefore, it is an important research topic for exploring the culture conditions for stem cells rapid proliferation without affecting their differentiation potentials as well as optimizing the compositions of their culture medium.